As facebook updated their developer blog with a note to migrate the facebook apps to OAuth 2.0 authentication, facebook notifies all the App Developers to do it as quick as possible if havent dont already. Facebook will become a complete HTTPS enabled platform very soon and apps are the only services that are not into this limit. You may have noticed while accessing many apps in Facebook, prompting you to Turn off SSL mode to continue accessing the app you have requested.

This may bring some possible security problems to the users of Facebook. Hence, Facebook is now completely transforming their Apps authentication to OAuth 2.0 which supports HTTPS protocol very much.
Facebook Connect Users
This migration is also necessary for users who using Facebook Connect on their weblog or website. Simply follow the instruction given here to complete the migration and enjoy using FConnect feature on your website.
Facebook OAuth 2.0 Migration
All Facebook Apps must migrate to OAuth 2.0 for authentication and expect an encrypted access token. The old SDKs, including the old JS SDK and old iOS SDK will no longer work.
Apps on Facebook Authentication and security migration
All Canvas and Page tab apps (that are not using FBML) must convert to process signed_request (fb_sig will be removed) and obtain an SSL certificate for use in ‘Secure Canvas URL’ and ‘Secure Page tab URL’ (unless you are in Sandbox mode).
manage_pages permission required to access user accounts (/me/accounts)
We are modifying access to the FQL page_admin table and the graph.facebook.com/me/accounts endpoint. Previously, with basic permissions granted, an app could go to this endpoint or the FQL table to access the list of a user’s apps and Pages. We are going to require that apps have the manage_pages permission in order to obtain access to this information.
Thanks for reading and please do share this post in Facebook to help more people to get ready with the Facebook OAuth 2.0 upgrade.